Rudder Data

Record 1

‘RUDDERS’

Character string 'RUDDERS' - may be shortened to 'R'

Record 2

'N' ‘B’ or ‘S’,

lR, lSEP, AR, , ,

'I','D’ or 'F'

Character string 'N', 'B' or 'S' to designate normal, Becker or Schilling rudder; rudder position (m) relative to midships (<0); rudder separation (m), rudder area (m2), rudder aspect ratio, maximum rudder angle (degs) (), character string 'I', 'D' or 'F' to designate rudder operation as independent, dependent (coincident rudder angle) or fixed at zero.

Note:
If Becker or Schilling rudders are designated, lift-drag coefficients must be included as explained below.

Typical values of the rudder aspect ratio are 1.2-2.2 and of the rudder area between 1.2 and 1.8% of LppT for each twin rudder and 1.5-3.0% for a single rudder.

Record 3

, , ,

Propeller pitch (m) and RPM corresponding to ahead and astern maximum thrust for fixed longitudinal propellers adjacent to rudders.

Typical pitch and RPM values for ahead and astern operation are given by

where D is the propeller diameter and T vessel load draught.

Optional lift and drag rudder coefficients can be included by

(This is mandatory for Becker and Schilling rudders.)

Record 4

‘LIFT-DRAG’

Character string 'LIFT-DRAG' - may be shortened to 'L'

Record 5

, ,

Rudder angle (degs), lift and drag coefficient defined by: